The present invention relates generally to warning systems. More particularly, the invention provides a method and apparatus for remotely activating one or more warning devices that may be dispersed across a geographic area.
Tornadoes cause widespread damage each year in the United States. In order to help minimize loss of life, many municipalities have installed tornado sirens that are activated when an approaching tornado is detected. Federal Signal Corporation of University Park, Ill., manufactures various sirens and controllers that can be activated when authorities determine that an emergency is imminent. SafetyCom Incorporated of Little Rock, Ark., similarly provides various sirens to warn residents of emergencies. Other systems are exemplified by U.S. Pat. Nos. 4,812,825 (xe2x80x9cTornado Warning Systemxe2x80x9d) and 6,034,608 (xe2x80x9cTornado Alarm Systemxe2x80x9d).
Although tornado sirens allow residents to take shelter in the event of an impending tornado, the means by which the sirens are activated sometimes results in alarming residents who are in no real danger of being affected by a tornado. Tornado sirens are often activated on a county-wide basis, thus alarming many residents who are far from the projected tornado path, but who happen to be within the county or predetermined geographic zone that is associated with an impending tornado risk. Alternatively, in some communities, emergency operators manually activate individual sirens based on a visual comparison of weather displays (or text descriptions of displays provided by the National Weather Service) with geographic maps showing the location of sirens in the area serviced by the emergency center.
In the latter situation, errors can arise based on the need to visually compare and judge distances and features on two different displays. Moreover, where only a generalized tornado warning is received, employees must use their discretion in determining whether to activate a given siren. The time required to translate a given warning into siren activation signals and the lack of meteorological training of many municipal or county employees can result in errors, delays, and false alarms.
Another problem relates to reliance on radio frequency transmission paths to activate individual sirens. Sirens are typically activated from a central control unit (e.g., a county-wide unit) by transmitting radio control signals over police radio frequencies, which can sometimes become so crowded or jammed during a weather emergency that radio control signals may not be received. It can also be difficult to determine whether a given siren has actually been activated after a signal has been sent.
It is expensive for municipalities to pay for employees to monitor and respond to tornado threats by activating sirens. For a small county with a few sirens, the job function maybe shared by an emergency 911 operator or a fire marshal, who often have other duties and job responsibilities. Counties or cities often cannot afford full-time meteorologists to pinpoint the likely path of a tornado and communicate that information to a county emergency center, which must then compare the warning information to a map showing the location of various sirens within the county or city. Two adjacent counties may have separate, incompatible warning systems that are operated by different people and activated on the basis of different information.
In addition to tornados, other meteorological and non-meteorological conditions can present substantial threats to a community as well. These include other meteorological phenomena such as flash floods, lightning strikes, and other dangerous meteorological conditions, as well as non-meteorological conditions such as a threat from a release of a hazardous material, volcanic eruption, pollution, and the like.
The aforementioned problems give rise to the solutions provided by the present invention.
The invention provides a system and method for activating warning devices, such as tornado sirens, in conjunction with a meteorological map display that shows the actual and/or predicted path of a tornado or other meteorological event. In one variation of the invention, a user can manually select one or more tornado warning devices by drawing a box or other encircling indicator around icons on a computer screen each representing the location of a tornado warning device. The selection can be made on a computer screen that simultaneously shows both the meteorological event and the location of each warning device. In another variation, activation can occur automatically by computer based on a comparison of a tornado location with the location of one or more warning devices.
A central weather prediction center can be remotely coupled to a plurality of tornado warning devices in dispersed geographic regions (e.g., different cities, counties, or states), thus avoiding the need for persons located in each of those regions to be responsible for activating sirens in the particular region. Remote activation can occur over telephone lines, packet switched networks, the Internet, frame relay networks, and the like.
Some aspects of the invention activate warning devices based on non-meteorological hazardous events, such as a release of hazardous materials, air pollution, volcanic eruption, and the like, based on a predicted or known plume associated with the affected area.